As the great Louis Armstrong was wont to sing: what a wonderful world! They are frying eggs on the roads of Hendon. Hemlines are up, tanned thighs on full display — and that’s just the blokes at The Times. It’s almost my birthday: 43 again, for a record 12th time. Andy Murray, England’s new Scottish hero (actually, England’s first Scottish hero ), is still on course to slobber over the silverware on Sunday. And, joy of joys, eco-warriers are back! Not only back, but squatting all over England, like a little army of high-minded frogs.

Funny how, in nice weather, outdoor agitation suddenly becomes popular. But on this sunny morn let us banish such cynicism, and rejoice that Britain is still full of people who refuse to lie down and let Big Business — or, even worse, Big Government — crush them. What was Tony Hancock’s immortal quip? “Does Magna Carta mean nothing to you? Did she die in vain?” Not while Swampy and his successors are around, she didn’t.

Actually, Swampy himself — muddied folk-hero of the Battle of Newbury Bypass — isn’t around much any more. It’s said that after posing as “alternative totty” for Just Seventeen magazine, his credibility in eco-warrioring circles sank so low that he retired to a yurt in North Wales.

But his spirit lives on. Nowhere more so than at Kew Bridge in London, where (as The Times reported) 30 squatters have taken over a Thames-side site owned by a big, brash developer, St George. There they have set up what they describe as an “ecologically sustainable” community. Sustainable in the sense that they plan to feed themselves by raiding supermarket skips and “liberating” out-of-date produce thrown away each night. “It’s about showing that you can live a simple life and be happy,” says their spokes-dude.

Hmm. It’s interesting how definitions of “a simple life” change. The Kew squatters use Twitter and Facebook to plan their campaigns, communicate their aims and tout for donors. And their idea of ecological sustainability does appear to rely to a large extent — a hypocritically large extent, you may feel — on the same supermarkets (with their vast carbon footprints of food freighted round the world) as the rest of us use. The only difference is that the squatters won’t pay for their food, which perversely seems to make them feel morally superior.

Even so, the sheer cheekiness of their actions — a hippy commune, digging a well, in Central London! — has tickled the public’s fancy. And the questions they raise are worth asking. Why has such a prominent site been derelict for 20 years? If the developers can’t devise a scheme that meets with planning approval they ought to let someone else do something more useful with the land. Then there’s the food aspect. How is it possible that 30 people can scavenge enough discarded grub to feed themselves indefinitely? What does that say about the obscene levels of waste in Western society, when half the world is starving? If the Kew squatters bring these questions to the fore, they will have done us all a service.

Another of this summer’s squats has more controversial aims. In Derby a “peace camp” has been set up on a site due for redevelopment next to Rolls-Royce’s factory. The protesters want Rolls-Royce to stop making reactor cores for nuclear submarines. They’ve agitated before. Last year ten of them (including three in their sixties) plunged their arms into quick-set concrete to form a human barricade round the plant’s entrance. It was a clever tactic, not because it rendered them immovable but because it landed them in court, thus giving them a priceless public platform from which to denounce Rolls-Royce for aiding “war crimes”. The judge wasn’t too impressed by that. But eight of them got off anyway, because the Crown Prosecution Service cocked up (what a surprise!) and pressed a charge of aggravated trespass when the protesters had actually been on a public highway.

Their tactics this time seem no less cunning. Their tree-houses at the peace camp were smashed up by bailiffs. So, like Swampy, some of them have literally gone to ground, hiding in 3ft-wide tunnels built to carry rainwater to the River Derwent. Food is apparently conveyed secretly each night (the tunnels run under half of Derby). Of course, if it rains heavily they will get very wet, and possibly drown. On the other hand, a long hot spell could make them very newsworthy, and very irksome for Rolls-Royce.

Causing maximum embarrassment is also the aim of the third, and probably most famous, squat of the summer — in the now-notorious derelict house in Brentford that is nominally the “second home” of the London Labour MPs Ann and Alan Keen. Or is it their first home? I think we’re all confused. Anyway, the six squatters have occupied the house to protest not only about MPs’ expenses but also everything from the Iraq War to the lack of affordable housing. I’m not sure we can blame the Keens for all of that, but so what? All’s fair in love and squatting.

I have friends, lodged politically somewhere between Norman Tebbitt and the Ayatollah Khamenei, who hate protesting squatters, arguing that they occupy land that isn’t theirs and waste a lot of other people’s time and money. That’s often true. Yet I find it impossible to be so hardline. These days the laws are stacked so heavily against individuals that I find myself instinctively siding with little people who make a stand against officious or wrong-headed authorities.

Anyway, posterity has a strange way of converting yesterday’s loonies into tomorrow’s heroes and visionaries. Five years ago I wrote on this page about Tony Wrench. He was an eco-warrior who incurred the wrath of the authorities (plus constant threats of eviction and punitive fines) by building a grass-roofed hut out of recycled wood and junk, so that he and his partner could live off the land, harming nobody, in a remote part of the Pembrokeshire Coast National Park (so remote that it took park keepers two years to notice the hut). I pleaded his cause, but privately I felt that it was pretty hopeless.

How wrong can you be? Last autumn, after a mere 11 years of merciless official hounding, Wrench was told that he could stay in his hut, because it was now deemed to conform to Pembrokeshire’s new “Low Impact” housing policy. As I said at the start, what a wonderful world!

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